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General Forums => The Mess Hall => Topic started by: Beachbum on April 14, 2006, 01:46:51 PM
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I ordered a Hesco RV0B4 camshaft and double roller timing chain and gear set from Hesco today and learned a few things while ordering it. I thought I would share what I learned, someone else might find it helpful. I talked to a guy named Benny or Denny, I'm unsure due to a bad telephone connection. Hesco recommends that valve springs be changed for this cam if you intend to run high RPM's, but they don't have to be, I chose not to change them. He also reommended the timing chain and gear set, this set is keyed in 3 different positions on the crank gear, advanced, straight up or retarded. He recommended to install it in the advanced position, this will give a good smooth idle and good vacuum at idle, to provide a good signal to the MAP sensor and prevent check engine light coming on etc. due to poor vacuum. He said this cam installed in this way will work very well with the fuel injection and should provide 20 to 25 extra ponies and increase torque sustantially from off idle to redline. I hope this info might help someone else who is cam shopping.
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What's the cam profile and how much did it hurt the wallet?
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Here is the published info on this cam, it is available on the HESCO website. Model # RV0B4, advertised duration 264, duration @ .050 = 214, lobe centers 110 degrees, lift .470. Cam and lifters = $239.00, double roller timing chain and gear set $149.00. I also purchased a valve cover gasket and timing gear cover gasket.
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That is the same cam I purchased I am still waiting for my head to come back from the machinest I decided to go whit the springs you need to have the sping seats machiened for the hight of the new springs.Just for your Info his name is Bennie and he is very helpful with any questions I have had. Did he also tell you about setting your preload on your lifters he said it should be at 50 thousandths.
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Did you also purchase the timing gear set to install your cam in the advanced position? I decided to stay with the stock springs mainly because I don't want the downtime waiting to get the head done, if I find out I need them then I can get it done. He didn't say anything about preloading the lifters, are you milling the head? If so maybe that's why he mentioned it to you, I don't believe the valves on the Jeep engine can be adjusted like a small block chevy, I'm not sure how they are preloaded. I'm going to look in my Chilton manual and see if I can find anything about it, if not the instructions that come with the cam will probably explain the procedure. Good luck !!!!!!!
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Yes I did get the double roller timing set.Yes I am milling my head but very minimal only 3 or 4 thousandths or so just to flaten it out.The preload should be at 40 to 60 thousandths but he said 50 is ideal.Bennie also said that if you rotate the pushrod in between your fingers as you tighten down on your rocker until pushrod gets snug then you want 50 thousandths preload from that point. Bennie sent me shims whith my cam when I ordered it.I have three different heads so I was not worried about down time and when I finaly get the head back I will be installing the head, cam, timing chain set, and adjustable feul pressue regulator, then we will see wat kind of differance it makes.
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I don't believe the valves on the Jeep engine can be adjusted like a small block chevy, I'm not sure how they are preloaded. I'm going to look in my Chilton manual and see if I can find anything about it, if not the instructions that come with the cam will probably explain the procedure. Good luck !!!!!!!
If you shorten the head .03 you have to raise the rocker arm .03 or you will be compressing the lifter .03 further. Or you could just put up the coin for pushrods that are .03 shorter :lol: .03 8)
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If it turns out that I want to install the valve springs and mill the head I'll probably do like you did, get another head and have it done, then install it (trying to keep costs reasonable). I see from your previous post you are also installing an adjustable fuel pressere regulator, are you going to install different injectors also? I've been wondering if changing the injectors would benefit the new cam, I'm going to wait and see how the jeep runs before ordering more engine parts. I have 2 more expensive projects to get done that I really need to concentrate on before more engine work. They are a Banks or Borla header along with a completely new exhaust system, this needs to be done before more engine work as it should help the engine breathe considerably better and help determine if new injectors are needed. The second big or expensive project I need to do is install 4.88 gears, along with brakes front & rear, and anything else I find that needs attention while doing these jobs. I'll just keep throwing a little money at the thing until I get it where I want it.
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I was told that I should not need bigger injectors so I will try it with out them and see how it runs.
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^ since you purchased an adjustable fuel pressure regulator you will be fine.
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I've got to ask a dumb question guys, what difference will the adjustable fuel pressure regulator make? I'm assuming increasing the fuel pressure will also increase fuel delivery to the engine. I'm guessing that the injector is open for so long, and the more pressure it has the more fuel it will deliver to the engine due to the increase in pressure. Did the fuel pressure regulator also come from Hesco? I've noticed they sell 1 for the 4.0L but didn't see 1 for the 2.5L. Maybe they are interchangable.
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^ Kind've. Under cruise conditions the ecu constantly changes the duty cycle of the injectors to keep the motor running at a 14.7 air to fuel ratio. (hard to do with the little narrow band O2 sensors). Under WOT (wide open throttle) i'm not to sure what the jeep is set up to do. Some vehicles under WOT the ecu doesn't use the O2 sensor, instead the ecu injects a certain amount of fuel determined by the MAP sensor and RPM. This WOT is like you were talking about, it is a set injector duty cycle. I'm not positive the jeep is set-up like this but it might be.
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Yes the fuel pressure regulator is from hesco.The box says its for a 91-95 4.0L and 91-99 2.5L.
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Why not go ahead and change the valve springs, it's relatively inexpensive and easy to do. I used Mopar performance springs #p5249464.
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Did you install your cam yet? Post an update when you do.
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I haven't installed the cam yet, the last time I was home on my days off it didn't sit still longer enough!!! I was also trying to decide whether to have the head freshened up and valve springs installed. I finally decided to go for it and got another head, it is currently in the machine shop being redone, valve springs, milled and valve job. I intend to get eveything installed when I go on my days off next time, the parts are piling up fast and my wife isn't going to let me get anymore until I get what I have installed. So far I have the following to be installed, cam, head, e fan, Bestop soft top with doors, all new seats, light bar. I did install a 4.0 TBS, hi output alternator and Accel coil last time I was off.
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I am interested to hear the result - currently my lifters are extremely noisy (which i understand is a common issue with the AMC 2.5) and i'd be interested to buy the cam & lifters as it seems to be priced fairly. I'll wait for your feedback before i do (i have a other things in the works in the meantime anyway). Thanks for the update and good luck with your setup. Keep us posted...
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Sounds like Beachbum is doing it right! and I dont see why .03 more compression on the lifter matters since we have self adjusting hydraulic lifters which pump up with oil to adjust up or bleed down to adjust down, there is about a half inch of adjustment within most lifters so as your valve train get worn they keep taking up the slack, this is in fact the only rocker adjustment if the engine does not have adjutible rocker arms! The main thing is to replace cam and lifters with good matched high quality stuff so you dont end up doing the job twice. I also hear there is a special tool for removing the Jeep lifters without having to pull the head.
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I have built plenty of engines and the hesco guy is right, it's good to change to a stronger timing chain and gear set if the cam has more lift it is going to compress the springs further which creates more resistance to the cam rotation. Changing the springs will allow a higher red line before the valves start to float but Jeep engines are better suited for lower RPM and more torque. Just install the new cam, lifters and timing set using a good prelube and stick with the 0 setting on your lower gear, trust me I have tried the + and - settings and you end up with a dead spot at the top or bottom of the power band that really sucks.
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Guardian7, I really appreciate your comments and input, although you've got me thinking now (I'm dangerous when I think, ha) Hesco recommended installing the cam in the advanced position, I realize that by advacing and retarding the cam all you are doing is moving the powerband either up or down on the RPM scale. They said in the advanced position I'll have a good smooth idle with strong vacuum. They also said it will pull strong from off idle to 5000 RPM. If you have experience with this particular cam installed in all three positions, I would appreciate all the info you can provide.
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I have more experience building V8 engines, performance timing sets usually come with 4 degree + or _ on the lower gear. I have built some some fast Datsun/Nissan Z engines also but did not mess with valve timings. With DOHC you can run 2 different cams and really have fun! My tests with the advanced settings usually put the powerband center someplace around 2000 Rpm and by 4000 there was nothing left. This is good for off-road rock climbing stuff but on the road really blows. Try the advanced position but remember its a lot of work to change back if your not happy. Its also good to first find out what the cam will do for your power in the zero position for comparison before trying the other positions. More lift and more duation will give you power throughout the powerband because you get more fuel and air into each cylinder. I think a 1 or 2 degree advance would be nice if you could find it, do you know what the hesco timing set offers?
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Hey I really appreciate your input. I'm going to go ahead and follow Hesco's advice and install the cam in the advanced position, they are the manufacturer and very reputable. They are also the comp. that is preparing my head. My Jeep still has 4:10 gears with 33" tires so I can definetly use extra low end power provided by the milled head ( 57cc's) and advanced cam. 4:88 gears are difintely on the horizon but probably won't happen until winter. Most of my wheeling is playing in the sand on the beach and going back and forth to my favorite fishing spots, I really need lowend power more than top end, it never sees hiway use and very little city use. After I get the 4:88's installed if I need a little more power towards the top end I can always change it back to the 0 position. I will post the results of this install when I get it done, it will be sometime in late June.
Beachbum says: Keep your wheels a spinnin and your girlfriends grinin!!!!
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i ordered the 274 cam, also with the timing set. i have the closed combustion chamber head. milled head and block .010 each for a total of .020 thousands( looking for close to 10:1 compression). replaced valve springs, and shimmed the rockers for a back to stock "preload" on the lifters. the head has been pocket and bowl ported, and port matched to the intake manifold. the intake manifold runners have been ported, and on the throttle body side the hole has been opened up to the spacer and the new "bored" out 4.0 throttle body. looks like i have found out that early full roller rockers from a v8 dodge will work, but have not tested it yet. ( will let you know)
i will post the link to my pics as soon as the parts come from the machine shop. this motor should make good power, im using the stock injectors as they flow more than enough for a "small" motor. 4.0 injectors will work, but their wide open flow rates are way to much for a 2.5 "4x4 torque) motor.
lastly, to asnwer the above question, when under WOT the computer is pre set and uses the temp sensor and map sensor, for fuel delivery
-james
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oh yeah thats my jeep behind jack here in honolulu
http://www.4bangerjp.com/forums/index.php?sid=ebd204b809b7c4e9b6d3447c4a11a5d7
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Sounds like your building it right, I'm really pumped up about getting mine put together. I've got a lot of parts to install, it's just hard to park the jeep long enough to work on it and the wife is bitc - er complaing about parts piled up in the living room, so I'll get it all done when I get home. Good luck with your installation and hope it's a screamer !!!!!!
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I have have not got mine installed yet I am going to order the ajustable roller rockers but I need an extra 1/2" of clerance in my valve cover so I would need a spacer or find two of the aluminum valve covers and cut them in half but leave one a 1/2" longer and reweld it together and I just have not found the time to get this issue worked out yet.
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finaly got everything installed over the long weekend I will post my opinon after I get a few miles on it.
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supryj4
You drive it Yet?
Updates boys, Lets hear some reviews. :D
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yeah, how is it - are you smoking the tires :D ?
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Ok I do not have alot of miles on it yet.Its not my daily driver and I have not had a lot of time to play.Let me start with a little info I already had 62 mm tb,spacer,rock-it intake,borla hedder and cat back,random tech cat,MSD ignition,flex a lite electric fan and with all of that from 4000 RPM to rev limt on computer was basicly my tourqe curve.The motor ran strong and sounded completly differant once I hit that 4k RPM.Now with the head work,cam,roller rockers,dobble roller timing set,and fuel pressure regulator it brought the tourqe cuve down to mid to low 2k RPM range all the way up untill the computer cuts it out.It did make a noticable differance but as always I was hoping for more.It did make a differance in the overall sound and smothness of the motor and how it revs up.It is alot more fun to drive around town. I got It up to 55MPH or so but have not hit the highway yet to see if it helps hold the higher speeds or not.I will keep you informed as I learn more.It does have a nice littel lope to it at idel it sounds good.I did notice that the other night when I was out and it was cooler out it semmed to run better could this be from my rock-it intake being mounted just above the valve cover and sucking in to much heat from the motor.Would that make a noticeable differance?Any input would be appriciated.And no I am still not smoken the tires yet I think it will take a supercharger or a 4.7L stroker to get there But my squerls are just a littel bit more angrer now :D
http://i71.photobucket.com/albums/i160/supryj4/100_2883.jpg
P.S. stock was many years ago so I cant realy compare it to what the differance betwen stock was and it was tbi then not mpi.
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that looks sweet man - i love the rockers. Are these the same as the ones for a 6 cyl? are they stock ratio or higher? do you need different length pushrods? Also, my lifters are noisy - i should get around and change them - are the lifters more quiet with the roller rockers?
For your question about the intake - it always makes a difference if you get in colder air - definitely if you get hot air in from undernieth the hood (which i do too :( ) it will lose HP/torque - hotter air means larger volume for same amount of O2 molecules so for same volume of air you will get less oxygen (plus the other downsides of hot air into the engine). You will still feel a difference at night even if you get a shorkle or air from somewhere outside the engine compartiment just because the temperature is lower at night.
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Yes they are stock 1.6 ratio they are adjustable rockers so I was able to set the correct preload of .050 with stock push rods. My lifters only had 6500 miles on them so I did not notice a differance in nois level. also I bought the rokers from hesco and they are the same as the 4.0 he just sold me 4 sets instead of 6.With the adjustable rockers you will need a 1/2" spacer for your valve cover to clear the taller rockers and a differant thermostat housing and spacer to move the housing out enough to still get the radiator hose on with out hitting the valve cover pain in the *** but it worked.